Several types of plants are faced with the problem of disposing aqueous effluents that contain relatively small quantities of hydrocarbons, and other pollutants such as iron, fly ash, and other dissolved and/or suspended solid materials.
Tank farms and related systems also have the problem of removing the hydrocarbons and other pollutants from the surface water in these areas prior to this water leaving their premises. Oil is frequently present in emulsified form in this surface water and is very difficult to separate from the water. The standards promulgated by the Environmental Protection Agency limit the discharge to water containing no more than about ten parts per million of oil per part of water. At present there is no simple, reliable system for separating trace amounts of oil and other suspended, miscible, and dissolved contaminants from contaminated water in one system.